Changes in phenolic compounds and browning during biological aging of sherry-type wine

Contents of hydroxybenzoic and hydroxycinnamic acids, hydroxycinnamic esters, and monomeric and dimeric derivatives of flavan-3-ol during biological aging of dry pale sherry white wine were measured and compared between wine without aging and wines in five different stages of aging. The results show a significant decrease in the levels of vanillic and ferulic acids, catechin, epicatechin and procyanidins B2 and B4, as well as an increase in those of syringic acid and procyanidin B1. According to the changes observed in polyphenol contents and the absorbance. data obtained at 420 nm, sherry-type wines seem to be protected from excessive browning during biological aging mainly as a result of the partial removal of flavan-3-ol derivatives, besides the effect of protection from om air contact carried out by the flor yeasts growing on the wine surface.